Quantitative Aptitude - Arithmetic Ability Questions

The value of 1/64 is equal to square of

An 80 litre mixture of water and acid contains 20% acid. How much acid should be added to make the acid 60% in the new mixture?

A sum of Rs 400 becomes Rs 448 at simple interest in 2 years. In how many years will the sum of Rs 550 amounts to Rs 682 at the same rate?

A train left 1 hour later than the scheduled time but in order to reach its destination 200 km away in time, it had to increase its usual speed by 10 km/hr. What is the usual speed (in km/hr) of the train?

P does half as much work as Q in 1/3 of the time. If together they take 15 days to complete a work, how many days will P take to do it alone?

The surface areas of three faces of a cuboid sharing a vertex are 20, 32 and 40 sq. mts. What is the volume of the cuboid in cub. m?

Six year ago Parvez’s age was same as the present age of Manish. If the present age of Parvez is one-fourth more than that of Manish's present age, then in how many years will Parvez’s age become double of Manish’s present age?

A number is divided into two parts in such a way that 30% of first part is 25 more than the 20% of second part. 50% of second part is 33.5 more than the 60% of first part. What is the number?